docs: def get_base(self, option):
          """
          Parse the base command option. Can be supplied as a 3 character code or a settings variable name
          If base is not supplied, looks for settings CURRENCIES_BASE and SHOP_DEFAULT_CURRENCY
          """
          if option:
              if option.isupper():
                  if len(option) > 3:
                      return getattr(settings, option), True
                  elif len(option) == 3:
                      return option, True
              raise ImproperlyConfigured("Invalid currency code found: %s" % option)
          for attr in ('CURRENCIES_BASE', 'SHOP_DEFAULT_CURRENCY'):
              try:
                  return getattr(settings, attr), True
              except AttributeError:
                  continue
          return 'USD', False